Too Much Rain in the Garden – What to Do
Rainwater is best for watering your garden, but too much rain is hard on your soil and your plants. I was watching the morning news the other day, and the weatherman said we had rain 15 days out of the last 16. It rained again that day.
My garden is soggy, but most of it is still in pretty good shape. In this article, we’ll talk about wet garden solutions, including steps you can take to prevent damage, and what to do after heavy rains hit. Wet weather might slow plants down, but it doesn’t have to end your gardening season.
Too Much Rain in the Garden – How Much is Too Much?
A general rule of thumb for gardening is that plants need roughly one inch of rain per week. Your garden may need more or less depending on soil conditions, ground cover, temperature, and other factors. Some areas, like the Pacific northwest, are known for their heavy rainfall. Other areas, like our part of Wisconsin, are hit with too much rain only rarely. Note: I always recommend talking to local gardeners if possible before starting a garden in a new area. Odds are it will save you a lot of headaches to learn from their experience.
You know you have too much rain when your garden turns into a muddy mess. Plants droop and may even start to rot. (Roots need air in the soil. Too wet/too waterlogged, and they can drown.) You may have standing water in low lying areas. Slug populations are likely to boom. Molds, mildews and other fungal issues can quickly escalate. Don’t panic, but do take steps to help out your plants.
Raised Beds or Raised Rows to Dry Our Wet Dirt
If you know too much rain is likely, or you have wet, heavy soil, raised beds are the way to go. Elevating your planting area keeps it dry earlier in spring so you can plant earlier, and allows excess rain to drain away from roots.
The simplest raised bed is soil that is mounded up in a planting area. Walking is restricted to paths between the plant beds, avoiding soil compaction in the beds. This works well with sheet composting. Pile organic matter where you want your garden bed in fall, let it compost over winter, plant in spring.
Low box frames directly on the ground are the next step up, like these ready to assemble cedar garden beds. Some folks also plant in tires, or build frames from concrete blocks or other materials.
The next step up is self-watering planter beds. These planters channel excess water down to a reservoir at the base for later use. An example is the GlowPear Urban Garden Self-Watering Planter.
In our garden, we mound up soil in beds, and also mound up individual rows where needed. Most years, the wind dries out my garden too much, so higher raised beds would be counterproductive. Our wagon wheel garden has permanent paths between beds. In the larger rectangle beds, we make seasonal paths and do raised rows or hilling. An obvious example of this is the potato patch. This year, hilling the potatoes is a “must do”, not a maybe. In between the rows it’s squishy, but in the rows the potatoes are dry enough to keep chugging along.
Adding Drainage for Wet Soil
If you have a short term problem, a simple trench funneling excess rain away from your garden may be enough. If soggy soil is an ongoing issue, a French drain or other drain tile may be a good idea. A French drain is a perforated pipe surrounded by gravel. Sod or other groundcover can be added over the top of the drain. The video below demonstrates the installation of French drain in a wet yard.
If you have a hillside in your garden that funnels water into your garden, it may make sense to put up a temporary barrier along the hillside to divert water away from your garden beds.
Mulch or No Mulch in a Wet Garden?
To mulch or not too mulch? My friend, Deb, shared her experience on Facebook:
Go light on the mulch. The mulch can actually slow the soil from drying out. One year when our area was basically flooded, we were able to see this in real life. About three rows of corn were mulched, and the rest was waiting for mulch. The mulched corn began to look washed out and grew very slowly while the unmulched pushed markedly ahead. Eventually it all yielded, but that was an interesting thing to see.
Too much mulch also creates more habitat for slugs to thrive. See “The Ultimate Guide to Natural Pest Control in the Garden” for tips on combating slugs and other pests.
On the flip side, mulch can help keep muddy soil from slashing up on the plants, reducing the chance of some soil borne fungal diseases. Mulch also spreads the force of your footfalls around, so mulched paths reduce soil compaction. I combine light mulch (1-2 inches of straw over old newspapers) with old boards in pathways. (Slugs sometimes hide under boards, so you can use them as slug traps. Flip boards over in the morning and remove the offenders sticking to the underside.)
Note: Later in 2017 we added five runner ducks to the mix, and they’ve been a tremendous help with the slug population later in 2017 and in 2018. You can read more about the Duck Patrol here.
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In some areas, I’ve skipped the straw mulch entirely. Instead, I’m letting some weeds grow as living mulch to soak up excess rain. Deb shared another snippet on using weeds for excess rain:
When my daughter worked at the landscape business, they would purposefully let weeds grow in some of the pots. These used up excess soil moisture without stressing the trees.
You can read more about using weeds in the post, “5 Reasons I Want Weeds in My Garden“.
Too Much Water on Tomato Plants
Our beloved garden tomato plants also take a hit from too much rain. Different problems your waterlogged tomato plants may have include, but are not limited to:
- Failure to thrive/drooping plants
- Fungal diseases/blight
- Blossoms but no fruit
- Cracked fruit
- Blossom end rot
Failure to Thrive/ Drooping Plants
First, let’s look at drooping, waterlogged plants. Tomatoes will put out new roots from the stem, so one option is to heap additional soil or compost around the base of the plant. This gives the plant a new root area above the wet soil. I used this to save my tomato patch during another extremely wet year. Even without added dirt, if you can improve drainage, with better weather the plants will likely recover.
Fungal Diseases/Blight
Fungal diseases love nothing better than damp conditions, and once started, they’re hard to stop. As mentioned above, light mulch will help slow down soil borne fungus. You can also remove leaves close to ground level to reduce the spread of spores. Some spores are carried on the wind, so you can’t avoid them entirely.
Growing tomatoes on a trellis improves air flow, reducing disease pressure. (This helps for other vine crops, too. See 5+ Terrific Tomato Trellises for trellis ideas.) Prune plants as needed to ensure good air flow and sun exposure. Dry conditions and sunlight both reduce fungal stress.
Remove diseased foliage and discard in the trash, or bag and take it to your local extension office for identification. (Clean clippers after use so you don’t spread the spores.) Cornell University has a good diagnostic page for tomato diseases.
To fight bad microbes with good microbes, consider using mycorrhizal fungi, compost tea or Effective Microorganisms in the garden to strengthen your plants’ defenses.
Blossoms But No Fruit
Pollinators have a hard time getting around in the rain, and wet pollen doesn’t carry well on the wind. For a variety of suggestions to help your tomatoes set fruit, see “Tomato Flowers but No Fruit – 9 Troubleshooting Tips.”
Cracked Fruit
Too much rain or moisture at one time can cause tomatoes to burst at the seams. This can also happen with other garden produce, such as radishes or melons. Once a fruit cracks, it’s best to use it as soon as possible. In the future, you can look for crack resistant varieties, or take steps to reduce soil wetness before the fruits are ripe.
Blossom End Rot
Blossom end rot is a black, rotten area at the blossom end of the tomato. It’s most common in extreme dry conditions, but also happens with extreme wet. The problem is caused because tomato plants can’t take up enough calcium from the soil. Common solutions include tomato fertilizers with added calcium, crush eggshells, garden line, and antacids. To learn more, visit “7 Steps to End Blossom End Rot and Get Rid of Black Bottomed Tomatoes“. Like cracked fruit, blossom end rot may also show up with other garden plants, such as summer squash or melons.
More Gardening Tips
Do you have other tips for dealing with heavy rains, or questions I haven’t addressed? Leave a comment below. As always, sharing is much appreciated. If you enjoy the post, let others know, too.
You may also find useful:
- Rainwater Harvesting
- Small Garden, Big Yield – 10 Tips for a Great Harvest
- 20 Things I Wish I Had Before the Flash Flood Emergency
